Nonlinear feedforward enabling quantum computation
A. Sakaguchi, Shunya Konno, Fumiya Hanamura, Warit Asavanant, Kan Takase, Hisashi Ogawa, Petr Marek, Radim Filip, Jun–ichi Yoshikawa, Elanor H. Huntington, Hidehiro Yonezawa, Akira Furusawa
Abstract
Measurement-based quantum computation with optical time-domain multiplexing is a promising method to realize a quantum computer from the viewpoint of scalability. Fault tolerance and universality are also realizable by preparing appropriate resource quantum states and electro-optical feedforward that is altered based on measurement results. While linear feedforward has been realized and become a common experimental technique, nonlinear feedforward was unrealized until now. In this paper, we demonstrate that a fast and flexible nonlinear feedforward realizes the essential measurement required for fault-tolerant and universal quantum computation. Using non-Gaussian ancillary states, we observed 10% reduction of the measurement excess noise relative to classical vacuum ancilla.